Plastic flow of a nanocrystalline/amorphous Al90Fe5Gd5 composite formed by rolling

Mechanically induced nanocrystallization has attracted much interest and is expected to be an alternative route for synthesizing nanocrystalline/amorphous matrix composites. However, little research has been performed on the mechanical behavior of these composites. Using nanoindentation, we have investigated plastic flow of a nanocrystalline/amorphous Al90Fe5Gd5 composite produced by rolling at room temperature. The nanocrystalline/amorphous matrix composite exhibits less-obvious serrations than the as-spun amorphous alloy. Using high-resolution transmission electron microscopy and atomic force microscopy, we observed the microstructure and morphology of indents. It is believed that the predominant deformation mechanism in the nanocrystalline/amorphous composite is the propagation of preexisting shear bands, in contrast to nucleation and propagation in the as-spun alloy.